In the past, there has been known a technique of causing two parallax images, captured from two points of view, to be displayed on a monitor so that a user who uses a dedicated device such as stereoscopic view glasses can view a stereoscopic image. Further, in recent years, there has been developed a technique of causing multiple parallax images (for example, nine parallax images), captured from a plurality of points of view, to be displayed on a monitor using a light beam controller such as a lenticular lens so that the user can view a stereoscopic image with the naked eyes. A plurality of images to be displayed on a monitor that can be viewed stereoscopically are generated by estimating depth information of an image shot from one viewpoint and performing image processing using the estimated information in some cases.
As medical image diagnostic devices such as X-ray computed tomography (CT) devices, magnetic resonance imaging (MRI) devices, and ultrasonography devices, devices that can generate three-dimensional (3D) medical image data (hereinafter, volume data) have been put into practice. Such a medical image diagnostic device generates a flat image for display by executing various pieces of image processing on volume data and displays the generated flat image on a general-purpose monitor. For example, the medical image diagnostic device executes volume rendering processing on volume data so as to generate a two-dimensional rendering image on which three-dimensional information for a subject has been reflected, and displays the generated rendering image on the general-purpose monitor.